Hydraulics and Pneumatics

Safety for Hydraulics and Pneumatics 211

"Safety for Hydraulics and Pneumatics" provides a complete overview of the best safety and injury prevention practices for fluid power systems. Fluid power systems rely on the use of highly pressurized liquids and gases. As a result, working with fluid power systems is associated with a variety of hazards, including risk of injection injuries as well as exposure to extreme temperatures and hazardous energy. Several devices and safety procedures can mitigate the potential for accidents and damage to system components.

Without a thorough understanding of fluid system safety standards, procedures, and devices, working with pressurized fluids can result in severe burns, poisoning, respiratory damage, intestinal bleeding, and death. After taking "Safety for Hydraulics and Pneumatics, " users will be able recognize how to prevent accidental injury and equipment damage when working with fluid power systems.

  • Difficulty Intermediate

  • Format Online

  • Number of Lessons 20

  • Language English


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Course Outline
  • The Force of Flowing Fluids
  • Pressurized Fluid Hazards
  • Personal Protective Equipment
  • PPE Requirements
  • Basics of Fluid Hazards Review
  • Hydraulic Fluid Exposure
  • Hydraulic Injection Injuries
  • Hydraulic Fluid Burns
  • Pneumatic Fluid Exposure
  • Sudden Shift of System Components
  • Inherent Risks of Power Fluids Review
  • Forms of Hazardous Energy
  • The Control of Hazardous Energy
  • Lockout/Tagout Mechanisms
  • Hazardous Energy Review
  • Other Safety Mechanisms
  • Fluid Power Tool Safety
  • System Faults
  • Preventive Maintenance
  • Safety Methods Review
  • Describe the dangers of working with pressurized fluids.
  • Describe the dangers of working with pressurized fluids.
  • Describe personal protective equipment.
  • Describe the PPE requirements outlined by OSHA.
  • Describe the risks associated with exposure to hydraulic fluids.
  • Explain the causes of most hydraulic injection injuries.
  • Describe the extreme temperature hazards present in fluid systems.
  • Describe the extreme temperature hazards present in fluid systems.
  • Describe why fluid system components can move unexpectedly.
  • Describe types of hazardous energy.
  • Describe steps that prevent the uncontrolled release of hazardous energy.
  • Identify lockout and tagout devices.
  • Identify other safety devices that prevent accidents and equipment damage.
  • Describe how to safely handle and operate fluid power tools.
  • Explain the causes of most fluid system faults.
  • Identify fluid system maintenance methods.
Vocabulary Term


A component in a fluid system that converts hydraulic and pneumatic energy into mechanical energy. Actuators are also known as effectors.


A protective cover that shields the chest and knees from fluids and debris. An apron may split below the waist so it can be tied around the legs to provide additional leg protection.


An expensive synthetic rubber that protects skin against various chemicals. Butyl resists oxidation, corrosion, and abrasion and remains flexible at low temperatures.


A protective structure that separates a working machine tool from the operator. Cage doors must be closed in order to operate the machine safely.

cap end

The side of a piston that is opposite the rod. The cap end is also called the blind end.


A device used to store an electric charge. A capacitor consists of one or more pairs of conductors separated by an insulator.


Placing a fitting on a conductor to block fluid flow. Capping is done to help de-energize a system.

check valve

A directional control valve that allows fluid to flow in only one direction. Check valves prevent back flow.


A fluid system component such as a pipe, tube, or hose. A conductor conveys liquids or gases throughout a fluid system.


The presence of foreign substances in a fluid system. Contamination is the primary cause of problems in fluid systems.


The deterioration of materials as a result of chemical reactions between it and the environment. Corrosion is irreversible and degenerative.


A type of linear actuator that uses a piston to produce motion in a straight line. A cylinder is also known as a piston actuator.

deep frostbite

A severe injury caused by exposure to extremely cold temperatures. Deep frostbite indicates there will be tissue loss.


The thick layer of living tissue below the epidermis that forms the true skin. The dermis contains blood capillaries, nerve endings, sweat glands, hair follicles, and other structures.

double-acting cylinder

A cylinder with a port at each end supplied with hydraulic or pneumatic fluid for both the retraction and extension of the piston. A double-acting cylinder is used where high force is required in both directions of fluid travel.


A multi-point cutting tool used to make round holes. Drills are usually made from high-speed steel or cemented carbides.


A protective device that blocks excessive noise from entering the ear. Earplugs vary in type and can be made from wax, cotton, foam, silicone, and rubber.

electrical energy

Energy created by the movement of electrons. Electrical energy can be converted into light, heat, or motion.

emergency cut-off valve

A safety device that halts all fluid action immediately. An emergency cut-off valve is located between the pump and the master valve.


The outermost layer of the skin that covers the dermis. The epidermis is nonvascular and nonsensitive.

first-degree burn

An injury caused by exposure to extreme heat that affects only the surface of the skin. A first-degree burn causes reddening of the skin.

first-degree frostbite

Superficial frostbite that affects only the surface of the skin. First-degree frostbite, sometimes called frostnip, causes the skin to become white and feel numb.

fluid power system

A power transmission network that uses the force of flowing liquids or gases to transmit power. A fluid power system may be hydraulic or pneumatic.


The push or pull that changes an object’s motion or state of rest. Force is calculated by multiplying the mass of an object by its acceleration.

force multiplication

The increase in available power, usually associated with tools and power transmission systems. Hydraulic and pneumatic drives may provide high force multiplication.

four-hand control

A control that requires two operators to start and stop the machine. Similar to a two-hand control, a four-hand control is used as a safety precaution and can consist of pilot valves or electric push buttons.

fourth-degree frostbite

Deep frostbite that affects the entire thickness of the skin and the underlying muscle, tendon, and bone tissues. Fourth-degree frostbite is the most severe form of frostbite.


An airlike fluid that expands freely to fill any space available, regardless of its quantity. Gases differ from liquids in that there are no forces keeping gas molecules together.


A protective hand cover that reduces the risk of injury and exposure to high temperature fluids. Latex, butyl, neoprene, and nitrile gloves are chemical- and liquid-resistant.


Tight-fitting eye protection that completely covers the eyes, eye sockets, and surrounding facial area. Goggles offer protection from impact, debris, and splashes.


A protective full-body cover that reduces the risk of exposure to fluids and debris. Gowns come in a variety of materials, including paper-like fiber, rubberized fabrics, neoprene, and treated wool and cotton.


A machine that uses an abrasive to wear away at the surface of a workpiece. Grinders provide an efficient way to shape and finish metals and other materials.

hand pump

A manual device that actuates valves in a hydraulic system. A hand pump can be used instead of a hydraulic pump.

hazardous energy

An energy that can harm people. Hazardous energy includes, but is not limited to, electrical, thermal, pneumatic, and gravitational.


A power transmission system that uses liquid conveyed in a confined conduit under pressure to accomplish work. Hydraulic systems differ from pneumatic systems in that they do not use gases.

hydraulic safety valve

A safety device that relieves pressure in a hydraulic system. A hydraulic safety valve is used in conjunction with a rotating cylinder and a check valve.

hypoallergenic gloves

Protective hand covers that are unlikely to cause an allergic reaction. Hypoallergenic gloves include butyl, neoprene, and nitrile gloves.


The innermost and thickest layer of the skin. The hypodermis helps regulate temperature and insulate the body, among several other functions.

injection injury

A small puncture of the skin or body tissue caused by high-pressure fluid. Injection injuries usually occur while operating or inspecting pressurized hydraulic equipment.

kinetic energy

Energy existing because of an object's motion. Kinetic energy is often harnessed, converted to other types of usable energy, or transferred to other objects.


A natural material made out of rubber. Latex is very elastic, strong, and may be biodegradable.


A fluid that has the ability to flow and take the shape of its container. A liquid's volume remains close to constant despite changes in pressure.

lockout device

A safety mechanism that holds a switch in an off position or covers the switch so that it is inaccessible. Only the person who has secured the lockout device on the switch is authorized to unlock it.


An OSHA standard that protects employees from injury. Once a device is under lockout/tagout, it is rendered inoperable.

lockout/tagout devices

A safety mechanism or warning label used to prevent the accidental release of hazardous energy during maintenance or service. Lockout/tagout devices identify authorized users.


A face cover that protects the mucous membranes that line the nose, mouth, and lungs from exposure to fluid, toxic fumes, dust, and debris. Masks are essential PPE when working with fluid systems.

master valve

A directional control valve used in hydraulic and pneumatic systems. Master valves are typically three-way or four-way valves.

mechanical advantages

The advantage gained by the use of a mechanism in transmitting force. Mechanical advantages are the ratios of force out of mechanisms to the force put in the mechanisms.


A moderately priced synthetic rubber that protects against various chemicals. Neoprene is high density and tear resistant.


National Institute for Occupational Safety and Health. A government agency related to the Center for Disease Control (CDC) that is responsible for conducting research in order to prevent work-related illnesses and injuries. NIOSH works closely with the Occupational Safety and Health Administration (OSHA) to protect employees in America.


A low-cost copolymer that protects against various chemicals. Nitrile is highly puncture resistant compared to latex.

Occupational Safety and Health Administration

OSHA. A government agency under the Department of Labor that sets the standards for working conditions in the U.S. The Occupational Safety and Health Administration ensures that employees work in safe and healthy environments.


Occupational Safety and Health Administration. A government agency under the Department of Labor that sets the standards for working conditions in the U.S. OSHA ensures that employees work in safe and healthy environments.

paint sprayers

A device with a container from which paint or other liquid is sprayed through a nozzle by air pressure from a pump. Paint sprayers spray fluid in a fine mist created by atomizing the fluid in an air jet.

Pascal’s Law

A principle that states when pressure is applied to a contained fluid the force is transmitted equally in all directions. Pascal's Law was established in the 1600s by French scientist Blaise Pascal.

personal protective equipment

PPE. Any type of safety equipment that workers wear or use to prevent injury in the workplace. Personal protective equipment includes safety glasses, gloves, masks, gowns, and earplugs.


Developed from gaseous, liquid, or solid hydrocarbons naturally occurring beneath the earth's surface. Refined petroleum oil is the most common hydraulic fluid base.

pilot valves

An auxiliary control device. Pilot valves actuate the master valve.

pinhole leak

The loss of hydraulic or pneumatic fluid through a small hole, usually found on a fluid conductor. Pinhole leaks can reduce system efficiency and cause serious injection injuries.


A disk or short cylinder that fits a tube closely. A piston moves up and down due to the force exerted by a liquid or gas.


A power transmission system that uses gas, such as compressed air, conveyed in a confined conduit under pressure to accomplish work. Pneumatic systems differ from hydraulic systems in that they do not use liquids.

potential energy

Stored power in an object. A component called an actuator converts potential energy to kinetic energy.

pounds per square inch

psi. A common unit of pressure measurement. Pounds per square inch is derived from the English system.

power tools

A tool that is powered by an external source, such as electricity, liquid, or compressed air. Power tools must receive regular maintenance and be properly handled to avoid injury.


Personal protective equipment. Any type of safety equipment that workers wear or use to prevent injury in the workplace. PPE includes safety glasses, gloves, masks, gowns, and earplugs.


The force per unit area exerted by a fluid against a surface with which it is in contact. Pressure is typically expressed in pounds per square inch (psi).

preventive maintenance

Maintenance performed while a machine is in working order to keep it from breaking down. Preventive maintenance includes lubricating, tightening, and replacing worn parts.

protective eyewear

Eye cover that reduces the risk of injury and exposure to fluid, dust, and debris. Protective eyewear includes goggles and safety glasses.


A mechanical device that moves fluids in a system by introducing flow into the network. The resistance to a pump's flow produces pressure.

rod end

The side of the piston that is attached to the rod. Sending pressurized fluid into the rod end of a double-acting cylinder causes the piston rod to retract.

safety blocks

A device used during maintenance to prevent injury by blocking the movement of components or locking components in place. Safety blocks are placed in a machine to prevent accidental movement of the machine components.

safety clip

A device used to secure a tool to a fluid line. A safety clip can also be a latch on a power tool that prevents the trigger from being depressed.

Safety Data Sheet

SDS. Mandatory information that must accompany almost every chemical in the workplace, except for items like cleaning supplies. Safety Data Sheets include details such as the hazards, precautions, and first-aid procedures associated with the chemicals.

safety glasses

Eye protection that shields the eyes from debris. Safety glasses may or may not offer vision correction.


A device which helps join systems or mechanisms together. Seals help contain pressure, prevent leakage, and control contamination.

second-degree burn

An injury caused by exposure to extreme heat that affects the first and second layers of the skin. A second-degree burn causes blistering but not permanent scars.

second-degree frostbite

Superficial frostbite that may affect part of the dermis as well as the epidermis. Second-degree frostbite causes the skin to swell and feel frozen and hard.

single-acting cylinder

A cylinder in which pneumatic or hydraulic fluid acts on one side of the piston only. A single-acting cylinder may rely on a spring to push the piston back in the other direction.


A flexible device used for controlled application of force or for storing and releasing mechanical energy. Types of springs include helical, leaf, and spiral.

superficial frostbite

A mild injury caused by exposure to extremely cold temperatures. Superficial frostbite indicates there is likely to be little or no tissue loss.


A lubricant consisting of chemical compounds that are artificially made. Synthetic oils are widely available and can be manufactured in part by using chemically modified petroleum components.

tagout device

A prominent warning label, such as a tag, that can be securely attached to a machine or power source to alert employees that equipment is not to be operated until the tag is removed. Tagout devices are used with lockout devices.

thermal energy

Energy resulting from the motion of particles. Thermal energy is a form of kinetic energy and is transferred as heat.

third-degree burn

An injury caused by exposure to extreme heat that affects the first, second, and third layers of the skin, including tissue below the skin. A third-degree burn is the most severe type of burn.

third-degree frostbite

Deep frostbite that affects the epidermis, the dermis, and the fatty tissue beneath the dermis. Third-degree frostbite, similar to second degree frostbite, causes the skin to feel hard.

two-hand control

A device that requires an operator to use both hands to start and stop the machine. Two-hand controls are used as a safety precaution and consist of pilot valves or electric push buttons.


The speed of an object or substance on a given course along which it moves. Unlike speed, velocity always implies a direction.